ORIGINAL_ARTICLEPREDICTION ALGORITHM FOR TORQUE RIPPLE REDUCTION IN DTC-BASED DRIVESIn direct torque control, the selection of an applied voltage vector is based on the measuredparameters at the beginning of the sampling period. The delay between the measurement and the application of the voltage vector is the origin of an extra torque ripple. In this paper, a new predictive controller is proposed for compensating this delay and reducing the torque ripple. The stator current is measured twice in each sampling period and its expected value at the end of the period is predicted according to a linear extrapolation algorithm. Therefore, none of the machine parameters are used in the prediction, and consequently, the algorithm is quite robust against machine parameter variations. The calculation of the electromagnetic torque is performed using the predicted value of the stator current. Therefore, the selection of the voltage vector is more realistic and prevents extra torque ripple. This controller is quite suitable for high power drives where the sampling frequency is low, and there is enough time for the extra measurements. Simulation and experimental results which confirm the ability of this method to considerably reduce the torque ripple are presented.http://ijsts.shirazu.ac.ir/article_2293_6c5b2a8ddd45315cdaa43ae301dfacd6.pdf2008-12-12T11:23:202018-08-15T11:23:2034335510.22099/ijsts.2008.2293Induction motor drivedirect torque controltorque ripplepredictive controllerSH.KABOLIkaboli@sharif.edutrue1Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of IranElectrical Engineering Department, Sharif University of Technology, Tehran, I. R. of IranElectrical Engineering Department, Sharif University of Technology, Tehran, I. R. of IranLEAD_AUTHORM. R.ZOLGHADRItrue2Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of IranElectrical Engineering Department, Sharif University of Technology, Tehran, I. R. of IranElectrical Engineering Department, Sharif University of Technology, Tehran, I. R. of IranAUTHORP.ESKANDARItrue3Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of IranElectrical Engineering Department, Sharif University of Technology, Tehran, I. R. of IranElectrical Engineering Department, Sharif University of Technology, Tehran, I. R. of IranAUTHORD.ROYEtrue4Polytechnic Institute of Grenoble, FrancePolytechnic Institute of Grenoble, FrancePolytechnic Institute of Grenoble, FranceAUTHORORIGINAL_ARTICLE(Aσ )Δ -DOUBLE SEQUENCE SPACES VIA ORLICZ FUNCTIONS AND DOUBLE STATISTICAL CONVERGENCEThe aim of this paper is to introduce and study a new concept of strong double Δ ( A ) σ -convergence sequences with respect to an Orlicz function, and some properties of the resulting sequencespaces were also examined. In addition, we define the Δ ( A ) σ -statistical convergence and establish someconnections between the spaces of strong double Δ ( A ) σ -convergence sequences and the space of doubleΔ ( A ) σ -statistical convergence.http://ijsts.shirazu.ac.ir/article_2294_7b3faf5ebb8fb2aa2b49a4f784cc4981.pdf2008-12-12T11:23:202018-08-15T11:23:2035736710.22099/ijsts.2008.2294Orlicz functioninvariant meansalmost convergencedouble statistical convergenceE.SAVASekremsavas@yahoo.comtrue1Istanbul Ticaret University, Department of Mathematics, Uskudar, Istanbul, TurkeyIstanbul Ticaret University, Department of Mathematics, Uskudar, Istanbul, TurkeyIstanbul Ticaret University, Department of Mathematics, Uskudar, Istanbul, TurkeyLEAD_AUTHORR. F.PATTERSONtrue2Department of Mathematics and Statistics, University of North Florida, Jacksonville, Florida 32224, USADepartment of Mathematics and Statistics, University of North Florida, Jacksonville, Florida 32224, USADepartment of Mathematics and Statistics, University of North Florida, Jacksonville, Florida 32224, USAAUTHORORIGINAL_ARTICLELINEAR PROGRAMMING PROBLEM WITH INTERVAL COEFFICIENTS AND AN INTERPRETATION FOR ITS CONSTRAINTSIn this paper, we introduce a Satisfaction Function (SF) to compare interval values on the basis ofTseng and Klein’s idea. The SF estimates the degree to which arithmetic comparisons between two intervalvalues are satisfied. Then, we define two other functions called Lower and Upper SF based on the SF. Weapply these functions in order to present a new interpretation of inequality constraints with intervalcoefficients in an interval linear programming problem. This problem is as an extension of the classical linear programming problem to an inexact environment. On the basis of definitions of the SF, the lower and upper SF and their properties, we reduce the inequality constraints with interval coefficients in their satisfactory crisp equivalent forms and define a satisfactory solution to the problem. Finally, a numerical example is given and its results are compared with other approacheshttp://ijsts.shirazu.ac.ir/article_2295_468f16722b798e7ccc781d7fd54c9b49.pdf2008-12-12T11:23:202018-08-15T11:23:2036939010.22099/ijsts.2008.2295Interval numberinequality relationequality relationsatisfaction functioninterval linear programmingA.ABBASI MOLAIabbasi54@aut.ac.irtrue1Faculty of Mathematics and Computer Science, Amirkabir University of
Technology, Hafez Avenue, Tehran, I. R. of IranFaculty of Mathematics and Computer Science, Amirkabir University of
Technology, Hafez Avenue, Tehran, I. R. of IranFaculty of Mathematics and Computer Science, Amirkabir University of
Technology, Hafez Avenue, Tehran, I. R. of IranLEAD_AUTHORE.KHORRAMtrue2Faculty of Mathematics and Computer Science, Amirkabir University of
Technology, Hafez Avenue, Tehran, I. R. of IranFaculty of Mathematics and Computer Science, Amirkabir University of
Technology, Hafez Avenue, Tehran, I. R. of IranFaculty of Mathematics and Computer Science, Amirkabir University of
Technology, Hafez Avenue, Tehran, I. R. of IranAUTHORORIGINAL_ARTICLEAUTOCORRELATION FOR A CLASS OF POLYNOMIALS WITH COEFFICIENTS DEFINED ON TIn this work we deal with the coefficients of A (e it ) 2 , where A is in a class of polynomialshaving Unimodular coefficients. We first present a technique that calculates lower bounds for particularautocorrelations and then in a more general case we present an upper bound for their maximal order.http://ijsts.shirazu.ac.ir/article_2296_56872c197938e0e404d49c7f95efc4cb.pdf2008-12-12T11:23:202018-08-15T11:23:2039139610.22099/ijsts.2008.2296AutocorrelationfrequencyFouier coefficientM.TAGHAVItaghavi@math.susc.ac.irtrue1Department of Mathematics, College of Sciences, Shiraz University, Shiraz, I. R. of IranDepartment of Mathematics, College of Sciences, Shiraz University, Shiraz, I. R. of IranDepartment of Mathematics, College of Sciences, Shiraz University, Shiraz, I. R. of IranLEAD_AUTHORORIGINAL_ARTICLEDOSIMETRIC EVALUATION OF A NEWLY DEVELOPED RADIOCHROMIC FILM FOR RADIATION PROCESSINGIn order to improve the performance of a newly developed radiochromic film, GIC-79, somedosimetric characteristics of this film have been studied based on relevant standard practice. The presentstudy describes some parameters that may affect the dosimeter response before, during, and after irradiation. The effect of absorbed dose rate on dosimeter response was determined by irradiating dosimeters at low absorbed dose rates with gamma rays. Calibration irradiations of dosimeters were performed with both gamma rays and also electrons to determine the effect of large difference absorbed dose rates on dosimeter response. In addition, post irradiation stability was obtained and also the temperature and humidity effects on the dosimeter response during the storage time prior to irradiation and post irradiation have been investigatedhttp://ijsts.shirazu.ac.ir/article_2297_7234ac0ffa0fca0d2f7bd6bc72de1224.pdf2008-12-12T11:23:202018-08-15T11:23:2039740110.22099/ijsts.2008.2297Dosimetryfilm dosimeterradiochromic filmgamma radiationelectron beamA.AKHAVANazakhavan@aeoi.org.irtrue1Radiation Applications Research School, Nuclear Science and Technology Research Institute,
P.O. Box 11365-3486 Tehran, I. R. of IranRadiation Applications Research School, Nuclear Science and Technology Research Institute,
P.O. Box 11365-3486 Tehran, I. R. of IranRadiation Applications Research School, Nuclear Science and Technology Research Institute,
P.O. Box 11365-3486 Tehran, I. R. of IranLEAD_AUTHORM.SOHRABPOURtrue2Department of Energy Engineering, Sharif University of Technology, Tehran, I. R. of IranDepartment of Energy Engineering, Sharif University of Technology, Tehran, I. R. of IranDepartment of Energy Engineering, Sharif University of Technology, Tehran, I. R. of IranAUTHORM.SHARIFZADEHmsharifzadeh@aeoi.org.irtrue3Radiation Applications Research School, Nuclear Science and Technology Research Institute,
P.O. Box 11365-3486 Tehran, I. R. of IranRadiation Applications Research School, Nuclear Science and Technology Research Institute,
P.O. Box 11365-3486 Tehran, I. R. of IranRadiation Applications Research School, Nuclear Science and Technology Research Institute,
P.O. Box 11365-3486 Tehran, I. R. of IranAUTHORORIGINAL_ARTICLEON EINSTEIN (α,β )-METRICS– In this paper we consider some (α ,β ) -metrics such as generalized Kropina, Matsumoto and F (α β )2α = + metrics, and obtain necessary and sufficient conditions for them to be Einstein metrics when βis a constant Killing form. Then we prove with this assumption that the mentioned Einstein metrics must beRiemannian or Ricci flat.http://ijsts.shirazu.ac.ir/article_2298_e9e30572a219839fc8b166c53a696227.pdf2008-12-12T11:23:202018-08-15T11:23:2040341210.22099/ijsts.2008.2298Einstein Finsler metrics(αβ ) - metricsSchur lemmaB.REZAEIarazavi@cic.aut.ac.irtrue1Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranLEAD_AUTHORA.RAZAVItrue2Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranAUTHORN.SADEGHZADEHtrue3Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranAUTHORORIGINAL_ARTICLEIONOSPHERIC ABSORPTION OF HF RADIO WAVE IN VERTICAL PROPAGATIONIn this study, absorption of high frequency radio waves in the ionospheric plasma have beeninvestigated. The wave equation was obtained in terms of ionospheric parameters. The numerical values ofthe absorption have been calculated for 4 MHz, 4.5 MHz and 5 MHz waves. The necessary parameters forcalculation have been obtained using an International Reference Ionosphere (IRI) Model. The altitudinal,diurnal, seasonal and the variations of absorption with frequency have been examined. The calculations showthat the highest absorption occurs in the D-region. The absorption is higher in summer than in other seasonsand is maximum at daylight. In addition, absorption decreases with the increase of frequency.http://ijsts.shirazu.ac.ir/article_2299_bf9f6139f8a03ab62b0f67f9b28d9c4d.pdf2008-12-12T11:23:202018-08-15T11:23:2041341910.22099/ijsts.2008.2299IonosphereHF waveAbsorptionI.UNALiunal@inonu.edu.tr,true1Department of Science Teaching, Faculty of Education, Inonu Univ., 44280 Malatya, TurkeyDepartment of Science Teaching, Faculty of Education, Inonu Univ., 44280 Malatya, TurkeyDepartment of Science Teaching, Faculty of Education, Inonu Univ., 44280 Malatya, TurkeyLEAD_AUTHORO.OZCANtrue2Department of Physics, Faculty of Science and Arts, Firat Univ., 23169 Elazig, TurkeyDepartment of Physics, Faculty of Science and Arts, Firat Univ., 23169 Elazig, TurkeyDepartment of Physics, Faculty of Science and Arts, Firat Univ., 23169 Elazig, TurkeyAUTHORM.CANYILMAZtrue3Department of Physics, Faculty of Science and Arts, Firat Univ., 23169 Elazig, TurkeyDepartment of Physics, Faculty of Science and Arts, Firat Univ., 23169 Elazig, TurkeyDepartment of Physics, Faculty of Science and Arts, Firat Univ., 23169 Elazig, TurkeyAUTHORORIGINAL_ARTICLEPROJECTIVELY RELATED EINSTEIN FINSLER SPACESThe main objective of this paper is to find the necessary and sufficient condition of a given Finslermetric to be Einstein in order to classify the Einstein Finsler metrics on a compact manifold. The consideredEinstein Finsler metric in the study describes all different kinds of Einstein metrics which are pointwiseprojective to the given one. This study has resulted in the following theorem that needs the proof of threeprepositions. Let F be a Finsler metric (n > 2) projectively related to an Einstein non-projectively flatFinsler metric F , then F is Einstein if and only if F = λ F whereλ is a constant. A Schur type lemma isalso proved.http://ijsts.shirazu.ac.ir/article_2300_1d2fa8ed46454558cc9c742c54cbf50f.pdf2008-12-12T11:23:202018-08-15T11:23:2042142910.22099/ijsts.2008.2300Projectively related Finsler metricsprojectively flatEinstein Finsler metricN.SADEGH-ZADEHnasrin_sadeghi@cic.aut.ac.irtrue1Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranLEAD_AUTHORA.RAZAVItrue2Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranAUTHORB.REZAEIarazavi@cic.aut.ac.irtrue3Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of IranAUTHORORIGINAL_ARTICLEVELOCITIES OF DUAL HOMOTHETIC EXPONENTIAL MOTIONS IN D3*In this paper the concept of Homothetic Dual Exponential Motions in D3 is discussed and theirvelocities obtained. Due to the way in which the matter is presented, the paper gives some formula and factsabout dual exponential motions which are not generally knownhttp://ijsts.shirazu.ac.ir/article_2301_ddbd28d4f0af1df8d5fe9132a5dc9bd1.pdf2008-12-12T11:23:202018-08-15T11:23:2043143410.22099/ijsts.2008.2301Dual numberdual vectorhomothetic motionexponential transformationV.ASILvasil@firat.edu.tr,true1Department of Mathematics Faculty of Art and Science Fırat University, 23119 Elazıg, TurkeyDepartment of Mathematics Faculty of Art and Science Fırat University, 23119 Elazıg, TurkeyDepartment of Mathematics Faculty of Art and Science Fırat University, 23119 Elazıg, TurkeyLEAD_AUTHORORIGINAL_ARTICLEBOUND STATE ENERGY OF DELTA-FUNCTION POTENTIAL: A NEW REGULARIZATION SCHEMEIn this letter we have proposed a new regularization scheme to deal with the divergent integralsoccurring in the quantum mechanical problem of calculating the bound state energy of the delta-functionpotential in two and three dimensions. Based on the Schwinger parameterization technique we argue thatthere are no infinities even in D dimensions. In this way we were able to compare our proposal with theSchwinger regularization approch.http://ijsts.shirazu.ac.ir/article_2302_eb38ee6e1732a8150067147ff55416f4.pdf2008-12-12T11:23:202018-08-15T11:23:2043543810.22099/ijsts.2008.2302Delta-function potentialbound state energysmeared propagatorsA.JAHANjahan@aut.ac.irtrue1Department of Physics, Amirkabir University of Technology, P. O. Box 15875-4413, Tehran, I. R. of IranDepartment of Physics, Amirkabir University of Technology, P. O. Box 15875-4413, Tehran, I. R. of IranDepartment of Physics, Amirkabir University of Technology, P. O. Box 15875-4413, Tehran, I. R. of IranLEAD_AUTHORM.JAFARItrue2Islamic Azad University, Urmia branch, Urmia, I. R. of IranIslamic Azad University, Urmia branch, Urmia, I. R. of IranIslamic Azad University, Urmia branch, Urmia, I. R. of IranAUTHORORIGINAL_ARTICLEON R-QUADRATIC FINSLER METRICSWe prove that every R-quadratic metric of scalar flag curvature with a dimension greater than twois of constant flag curvature. Then we show that generalized Douglas-Weyl metrics contain R-quadraticmetrics as a special case, but the class of R-quadratic metric is not closed under projective transformationshttp://ijsts.shirazu.ac.ir/article_2303_b1d104fd19fc0b74b7c8c77b82ef8f94.pdf2008-12-12T11:23:202018-08-15T11:23:2043944310.22099/ijsts.2008.2303R-quadratic metricLandsberg metricgeneralized Douglas-Weyl metricB.NAJAFInajafi@shahed.ac.irtrue1Department of Science, Shahed University, Tehran, I. R. of IranDepartment of Science, Shahed University, Tehran, I. R. of IranDepartment of Science, Shahed University, Tehran, I. R. of IranLEAD_AUTHORB.BIDABADtrue2Department of Mathematics and Computer Science, Amir Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science, Amir Kabir University, Tehran, I. R. of IranDepartment of Mathematics and Computer Science, Amir Kabir University, Tehran, I. R. of IranAUTHORA.TAYEBItrue3Department of Mathematics, Faculty of Science, The University of Qom, Qom, I. R. of IranDepartment of Mathematics, Faculty of Science, The University of Qom, Qom, I. R. of IranDepartment of Mathematics, Faculty of Science, The University of Qom, Qom, I. R. of IranAUTHOR